In typical cellular wireless communications, each end-user device (e.g., cell phone, personal digital assistant, wirelessly equipped personal computer, etc.) subscribes to service from a given cellular wireless carrier (i.e., service provider) known as the device's home carrier. In practice, the home carrier will operate one or more radio access networks including base stations that radiate to define wireless coverage areas in which the end-user devices can operate. When a device enters into coverage of its home carrier's network, the device may register with the home carrier network and may then engage in wireless communication service via the home carrier's network, and the home carrier may accordingly charge or debit a service account of the device.
Although a typical cellular carrier may strive to offer wireless coverage throughout a region, such as nationally in the United States for instance, the carrier may not actually operate radio access networks in all locations throughout the region. To fill in gaps where the carrier does not operate its own radio access networks and thus where the carrier does not itself provide coverage, the carrier will typically enter into roaming agreements with other carriers. Under a roaming agreement, another carrier may agree to provide service to the home carrier's subscriber devices when the devices operate in the roaming carrier's network. Thus, when a device enters into coverage of a roaming carrier's network, the device may register for service with the roaming carrier's network and may then engage in wireless communication service via the roaming carrier's network. In accordance with the roaming agreement, the roaming carrier may then report that usage to the home carrier and may charge the home carrier for the usage. In turn, the home carrier may then pass that charge along to the service account of the device, or, for certain users, the home carrier may absorb the charge.
As a general matter, a home carrier may prefer to have its subscribers operate in coverage of the home carrier's network, rather than in coverage of a roaming carrier's network. One reason for this is that the home carrier will typically profit more when the home carrier charges the subscriber for use of the home carrier's network and services than when the home carrier merely passes a roaming carrier's charges along to the subscriber or absorbs the roaming charges. Another reason for this is that, when a subscriber is roaming, the subscriber may not benefit from full access to the home carrier's services and support, which may lead to poor user experience.
In addition, a home carrier may itself provide different types of coverage areas for its subscribers, and the home carrier may deem certain ones of its coverage areas to be higher priority or more preferable than others, just as the home carrier may deem its own coverage areas to be higher priority or more preferable than its roaming partner's coverage areas. For instance, in a given location, the home carrier may operate both a high-speed coverage area (such as a 4G or faster coverage area) and a lower-speed coverage area (such as a 3G coverage area), and the carrier may prefer that its subscriber devices operate in the high-speed coverage area so as to benefit from improved user experience.